NPIPM:Dermaptera
Authors: Ashley Mueller, Buyung Hadi
Identification
Eurpoean earwigs, a common species in the U.S., are reddish-brown in color and their legs are pale yellow. The shape of adult earwigs is elongated, and they are slightly flattened. When fully grown, they are about 16 mm long. Earwigs have long antennae, but their notable characteristic is the forceps protruding from their hind ends. Males tend to have larger and more inward-curving forceps than females. Earwigs have chewing mouthparts. If disturbed, earwigs can emit a noticeably foul odor. The name “earwig” comes from an old European superstition that earwigs enter peoples’ ears and bore into the brain.
Habitat
Earwigs are found in many habitats outdoors. They are nocturnal, and during the day they hide in moist cracks and crevices. They feed on soft-bodied pests like aphids and on insect eggs, decaying plant materials, herbaceous parts of ornamental plants, and soft fruits.
Life Cycle and Seasonal History
In the spring or summer, earwig eggs are laid into the ground in moderate-sized batches of 25-50. Females are maternal and are protective of the eggs and the nymphs, and they will stand guard near the burrow where the eggs were laid. Eggs laid in the spring hatch in a little over two months, while eggs laid in the summer hatch in about three weeks. Nymphs go through four stages and two development phases as they grow into adults, becoming more independent in foraging for food. Adulthood is reached late summer, and this is when mating occurs. Most earwig species overwinter as adults.
Human Interaction and Urban Impact
Earwigs are beneficial because they feed on soft-bodied pests such as aphids and on insect eggs. However, they can be of economic importance because they also feed on soft plant tissues such as leaves and fruits. This behavior can be unfortunate for the home gardener.
Earwigs may pose a problem when large numbers try to enter homes for shades, shelter, and moisture. Earwigs may feed and survive on pantry food items although they are not known to lay eggs and reproduce indoors. Despite the menacing pincer-like protrusion in the hind end of the insect, earwigs do not directly harm humans or pets. The pincer-like structure on an earwig’s hind end is termed cerci (pronounced “sir-see”) and is used as a defensive mechanism and to capture preys.
Prevention and Management Approaches
Control of earwig indoors hinges mainly on excluding earwigs from entering homes. Earwigs enter human dwelling through cracks in foundations and gaps around doors or windows. Caulk the cracks around doors, windows, foundations, and outdoor water faucets. Weather strips may also be used to seal gaps around doors and windows to prevent earwig entry. Earwigs prefer damp and shady shelter provided by pot plants, mulches, leaf debris and firewood piles. Removing such hiding areas from around the foundation and creating a clean, dry border around the house foundation should discourage further earwig invasion indoors.
Earwigs found in homes are best controlled by vacuuming or killed by hand. Because earwigs are not known to lay eggs indoors, a continual problem with earwigs signals continuous invasion from outdoor sources. In the case of bad infestation indoors, consider doing perimeter spraying on the house foundation using insecticides labeled for this type of application. Always use precaution and follow the label carefully before using any insecticide. Insecticides have a certain amount of toxicity to mammals; children and pets are especially at risk.
Pesticide application in home gardens is not a good solution for an earwig problem. Most synthetic pesticide products available for home gardens have a broad spectrum and will kill not only the pests but also the beneficial insects like predatory beetles, parasitoid wasps, and pollinator bees. As an alternative least-toxic solution, bait trapping the earwigs should work to reduce the insect’s population to non-threatening levels. A homemade baited trap can be prepared by cutting up a hole on the lid of a used container. Bait the trap with fish or vegetable oil and set the trap(s) nearby the plants where the most earwig populations are seen. Earwigs are attracted to the smell of the oil and the ones plunging into the trap are not able to climb out. Remove the dead earwigs, kill the live ones by submersing them in soapy water, and replace the bait (e.g. fish or vegetable oil) regularly as needed. Generally, the trap does not attract a lot of other insects that can be beneficial to the garden. In this way, the earwig population can be reduced without risking the beneficial insect community.
Other Online Resources
For information regarding labels of chemical control options, please visit NPIC MAPL
